Apparatus for separating particles of varying size or density



F. KOCH.. APPARATUS FOR SEPARATING PARTICLES 0F VAHYING SIZE 0R DENSITY.

APPLICATION FILED MAR. 24, I919- Patented Nov. 9, 1920.

3 SHEETSSHEET l.

F. KOCH.

APPARATUS FOR SEPARATING PARTICLES 0F VARYING SIZE 0R DENSITY. APPLICATION FILED MAR. 24, 1919.

3 SHEET S-SHEET 2.

1,358,375, I Patented Nov. 9, 1920,

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APPARATUS FOR SEPARATING PARTICLES 0F YARYING SIZE 0R DENSITY.

APPLlCATION FILED MAR.24, 1919, A

1,358,375; PatentedNOmQ, 1920.

s SHEETSISHEET 3.

UNITED STATES rm'rz xocn, or ST. PAUL, MINNESOTA.

APPARATUS FOR SEPARATING PARTICLES 0F VARYING- SIZE OR DENSITY.

Specification of Letters Patent.

Patented Nov. 9, 1920.

A Application filed March 24, 1919. Serial No. 284,853.

To all whom it may. concern.

Be it known that I, Fnrrz KooH, a citizen of the United States, residing at St; Paul, Minnesota, have invented a certain new and useful Improvement in Apparatus for Separating Particles of Varying Size or Density, of which the following is a full, clear, and exact description, such as, W111 enable others skilled in the art to which it appertains to make and use the same.

This invention relates to devices of the character that are used for separating II11X- tures of different materials or for classifying or separating particles of the same material of different sizes into different groups.

One object of my invention is to provide an efficient apparatus of simple design for separating particles of varying size or varying density, or both, into separate and dlS- tinct groups.

Another object is to provide an apparatus by which a mixture of different materials containing groups of particles of approximately the same size but of widely different relative densities can be separated in such a manner that one material will be separated from the other and the particles of the respective materials will besubdivided into different groups containing different sized particles.

Another object is to provide a separating apparatus whose capacity is considerably greater than devices of the character now generally used for separating mixtures or for classifying or subdividing the particles of a material into different groups; which is of such simple construction that it can be easily maintained in operative condition and which is so designed that it can be adjusted easily to accurately control or govern the separation of the materials or the particles of the material passed through the apparatus.

Briefly described, my improved apparatus comprises means for discharging a mass of mixed particles by centrifugal action into the air in such a manner that said particles will spread out and form into curtains of flow containing equivalent particles, due

to the combined action of gravity and the resistance of the surrounding atmosphere, and means for collecting in different zones the particles constituting said curtains of flow. I have herein used the term equivalents or equivalent partlcles to mean particles which are of approximately the same size and density and also particles which, although of a substantially. different. slze and substantially different denslty, follow the same path-of travel in sectlon as the particles first referred to, due to the combined influence that gravity and theresistance of the surrounding air exert on same. Accordingly, wherever the terms just mentioned occur in the claims, the should be construed as meaning the part1- cles that constitute a curtain of flow or which collect together in the same zone and not necessarily as meaning particles of the same size and density. I have also used the term density in the sense that it is commonly employed, namely, to I'nean relative density or specific gravity.

The means which discharges the particles into the air by centrifugal action is so c011- structed that all of the particles will be discharged from same at substantially the same horizontal or outward velocity and the means that collects the particles in different zones or groups preferably consists of collecting receptacles which are so arranged with respect to the means that discharges the particles into the air that each group may contain particles of varying size or varying density, or both, according to the nature of the material or materials being run through the apparatus. In order that the apparatus may be used successfully for separating mixtures of different materials containing groups of particles of the same size but of widely different densities and subdividing the particles of each material into different groups, I provide some or all of the collecting receptacles with screens that cause the mass of particles that enter a collecting receptacle or which collect in the same curtain offlow to be separated into two or more groups containing different sized particles, thus enabling the apparatus to be used for separating mixtures of materials 'that cannot be separated by the ordinary screening process, due to the fact that the particles of each material which are of the same size will pass through the same meshes of the screen, and will be separated from one another without relation to the difference in their densities.

The separation of the particles into different curtains of flow is effected primarily by the combined action of gravity and the resistance of the surrounding air into which the particles are discharged, but if desired, other means can be used to assist ravit in carrying the particles downward y an to modify the resistance which the surroundin air offers to the movement of the parose such for exam le as a current 0 air or gas or a stream of liquid that merely operates to deflect the articles downward y from their natural pat or a counter current of air or gas or stream of liquid that flows in an opposite direction to the approximately horizontally curved path of travel of the particles, and thus decreases the horizontal velocity of the particles. .The separation of the particles can be accurately controlled or governed by varying the speed of rotation.

of the means that imparts the initial velocity to the articles and discharges them centrifugally nto. the air; by va ing the position o the collecting receptac es with relation to. said means, elthervertically' or hor- I izontally, or both; or b modifying the force or direction of flow o the medium used to deflect the particles from their natural path or to retard the velocity of the particles in a horizontal direction with the object of further modifying their respective paths of travel.

, Mfyimproved apparatus can be used succe'ss ully for separating many kinds of mixtures or for separating the particles of many kinds of materials into more or less uniform groups. It is particularly adapted, however, for separating sand from gravel, ores from their concentrates, mixtures of pulverized materials containing impurities and various mixtures of materials that can not be separated by the ordinary screenin process as'well as those that can, due to t e fact that the materials "constituting the mixture contain particles of substantially the same size that-will pass through the same meshes of the screen.

Figure 1 of the drawings is a vertical sectional view of an apparatus constructed in accordance with my invention.

Fig. 2 is a top plan view of the rotor of said apparatus, partly broken away to illustrate the radially-disposed vanes or guiding devices on said rotor.

Fig. 3 is a vertical sectional view, illustrating another form of my invention.

termine t Figs. 4, 5 and 6 are views, partly in side elevation and in vertical section, illustrating other forms of rotors that may be used.

F igure 7 is a top plan view of a portion of the rotor shown in Fig. 6, and

Fig. 8 illustrates another means that can be used for spreading out the particles and discharging them'into the air.

Referring to the drawings, A designates a hopper for holding the partlcles to be separated, B designates a rotor consisting of a rotatable member arran ed horizontally below the hopper A in sue a manner that the particles in'said hopper will be fed downwardly into said rotor by gravity and then discharged from said rotor by centrifugal action into a horizontal or substantially horizontal plane, 'C designates a vertically-dis- %osed shaft that supports and turns the rotor and D designates a drive shaft for operating the shaft C, said drive shaft-being provided with a gear 1 that'meshes with agear 2 on the shaft C. The rotor B is composed of two horizontally-disposed disks 3 and 4 arranged one above the other and spaced apart so as to form a chamber for holding a mass of the particles to be separated, the bottom disk or plate of the rotor being of considerably greater diameter than the top disk 4. It is immaterial, however, Whether the to disk of the rotor is of less diameter orof t e same diameter as the bottom disk 3.

The hopper A is provided with a discharge spout 5 that pro ects downwardly into an annular flange 6 on the top plate of the rotor and the rotor is. referably equipped with a number of radia y-dis osed vanes or blades 7 arranged vertically etween the top and bottom plates of the rotor at some distance from the center of the rotor, as shown in Fig. 2, said vpnes guiding the particles outwardly away from the axis ofrotation of the rotor. When the rotor is in operation a mass of the particles which have been previously fed downwardly into the rotor from the hopper A will be discharged centrifugally from the rotor into a horizontal or substantially horizontal plane, as shown in Fig. 1, preferably at a high velocity.

As soon as the particles leave the rotor gravity tends to pull them downwardly and the resistance of the surrounding air tends to retard the outward movement of the particles or the movement of the particles in a .horizontal or substantially horizontal direction. The kinetic'energy of the particles determines the degree to which they are capable of overcoming the air resistance. Accordingly, several factors cooperate to dee paths-of travel of the particles after they leave the rotor, namely, the kinetic energy of each particle, the size of each particle and the weight of each particle. e kinetic energy of each particle depends upon its weight and horizontal velocity, and

the air resistance to which each particle is subjected as it moves outwardly away from the rotor depends upon the size of the particle. The downward pull that gravity exerts 0n the particle depends on the weight of the particle. As the particles are discharged from the rotor they spread out and separate into curtains of flow containing equivalent particles. It is, of course, obvious that particles of the same size and of the same relative density will take the same downwardly curved path, and thus collect together in the same curtain goof flow. This curtain of flow, however, ma contain other particles which are of a di erent size and of a different relative density, depending upon the character of material being run through the apparatus. Inorder to more clearly describe the separating action, I will assume that two round particles of the same rela-:

tive density but one having twice the diameter of the other are discharged from. the rotor at the same horizontal velocity. Both particles have the same acceleration earthward, for although the larger particle has eight times the downward pull exerted on it by gravity, it also has eight times the inertia which gravity has to overcome. The larger particle has eight times the kinetic energy of the smaller particle, because its weight is eight times that of the smaller particle. The air resistance proximately upon the cross-sectional area presented. In other words, the larger particle encounters four times the air resistance of the smaller. In cacao both particles would follow the same parabolic path. In air, however, since the larger particle has eight times the power to overcome the resistance of the. air, and has onlyfour times the resistanceto overcome, said larger particle will retain its horizontal velocity longer .than the smaller particle, and consequently, will be thrown outwardly farther than the smaller particle. As another example, assume that two particles of equal diameter but one having twice the relative density of the other are discharged from the rotor at the same horizontal acceleration earthward is but the kinetic energy of the particles or the power of the particles to overcome air resistance are diflerent, the denser particle having twice the kinetic energy of the less dense particle. Since the size of both particles is the same the. air resistance on both particles is the same, but the denser particle has more power to overcome the air resistance, and accordin ly, can travel out wardly fartherifrom tiie rotor. When I have referred to one particle as being thrown outwardly farther than the other, or travelagain the same,

ing farther away from the rotor, I have asdepends ap velocity. Their level, for ifone-particle is three feet away from the rotor at a'level of four inches below the rotor, a different particle which is only two feet away from the rotor at that same level will be at a lower level, if it is following its natural path, when it reaches a distance of three feet outwardly from the rotor. If the material being passed through the apparatus is com osed of particles of the same density but 0? different sizes, the largest particles will collect in the zone arranged farthest away from the axis of rotation of the rotor and the remainder of the particles will collect in the intermediate zones laying between the outer zone and the rotor, according to the sizes of said particles. These zones, however, merge insensibly into one another. The gradation contains no abrupt transitions. If, however, the material being passed through the apparatus is composed of different sized particles of different density, each collecting zone will contain particles of the same density of substantially the same size and particles of a difierent density of a considerably diiierent size. In other words, if a mixture composed of a very dense material and a material of considerably less density is passed through the apparatus,

each collecting zone will contain particles of the denser material of substantially the same size and particles of the less dense material of considerably greater size, assuming, of course, that the less dense material is of such a character that some of the particles of same will travel outwardly far enough to reach the outermost collecting zone.

In the apparatus shown in Fig. 1 the col lec'ting zones are formed by three annular troughs 8, 9 and 10 arranged one within the other in concentric relation with the rotor H and in a lower horizontal plane than said rotor. The number and form of the collect ing receptacles are immaterial, however, as the number and arrangement of the collecting zones depend upon the number and limits of the grades or groups into which it is desired to separate the particles. In the form of my invention shown in Fig. 1 each of the troughs above referred to is provided with a vertical partition that divides the interior of the trough into two concentrically arranged compartments, one of which is provided at its upper end with a screen. For example, the troughs 8, 9 and 10 are provided with partitions 8 9 and l0 respectively that divide the interior ofsaid troughs into separate and distinct compartments, three of said compartments being provided with screens 8, 9 and 10* arranged in sucha manner that one compartment of each trough is protected at its screen. Accordingly, the particles that enter each trough, or which constitute each curtain of flow, will be subdivided into two upper end by a a signed for handling some kinds of materials the screens just referred to will be omitted and in certain instances, some but not all 0 the collecting receptacles will be equipped with screens and subdivided into separate compartments. While I have shown each collecting receptacle as comprising two com partments, it will, of course, be obvious that the particular number of screened compartments in each collecting receptacle is immaterial.

The apparatus shown in Fig. 1 is also pros vided with means for causing a current of air to pass through the lane into which the particles are discharge from the rotor in such a manner that the less dense articles will be sharply deflected and the ot er articleswill be deflected progressivelyft ose of greatest density or size least, thus enhancing the separating effect. Said means consists of a suction fan E arranged horizontally below the rotor B with its inlet presented upwardly, as shown in Fig. 1, so that when the fan is in operation a current of air will flow downwardly and at an inwardly inclined angle through the horizontal or substantially horizontal plane into which the particles are discharged from the rotor B, as indicated by the arrows'in Fig. 1. In addition to enhancing the separating effect, the fan E' collects the fine dust that is mixed with the particles and forces said dust away from the apparatus through an eduction pipe 11. The blades of the fan E are preferably directly connected to the shaft C so that the fan will be operated from the same source that drives the rotor and in the form of my invention 'shown in big. 1 the fan is provided with a substantially funnel-shaped intake 12 whose outer edge terminates at the upper edge of the inner wall of the trough located nearest to the rotor. Various other means can be used, however, to assist avity in carryin the particles downward y and to modify t e resistance which the surrounding air offers to the movement of the par ticles in a horizontal direction.-

In order to enable the apparatus to be accurately controlled or governed, it is so constructed that the speed of the rotor B can be varied,.thereby changing the initial velocity that is imparted to the articles. The rotor B is also so constructe that it can be raised and lowered with relation to the collecting troughs. In the apparatus shown in Fig. 1 the drive shaft D is provided with a stepped pulle '13v so as to enable the s dof the rotor to varied, and the rotor is splined to the upper end of the shaft C in such a manner that it can be raised and lowered by increasin or decreasing the number of shims 14 t at are arra ed, between the upper end of the shaft C and the rotor. The above is only one of many ways, however, for varying the speed of the rotor and for changing the position of the rotor with relation to the collecting troughs.

While I have referred to the rotor as being constructed in such a manner that it discharges the particles into a horizontal or substantially horizontal plane, this is not essential to the successful operation of my apparatus, as some success can be obtamed by a discharge into a plane other than a plane dis osed at right angles to a vertical plane.

ccordingly, I do not wish the term horizontal to be construed in a rotor is shown in Fig. 5, wherein the rotor consists of a horizontally-disposed drum B provided at its periphery with holes 15' through which the particles are discharged from the rotor. In Figs. 6 and 7 of the drawings I have illustrated a rotor B consisting of a horizontally-disposed plate or disk provided on its upper side with radially-disposed ribs or partitions 16 provided with flanges 17 that slope upwardly and outwardly away from the center of the rotor, said flanges 17 being spaced apart so as to form slots 18 between said flanges. A rotor of the construction above described is particularly adapted for handling the contents of a ball grinder, owing to the fact that the contents of the grinder, together with the balls of the grinder, can be dumped onto the rotor B The balls of the grinder and the relatively large particles of the material which are too large to pass through the slots 18 between the upwardly curved flanges 17, ride upwardly on said flanges 17 and are discharged centrifu' gally from the rotor. The finer articles of th material pass through the s ots 18 and the separated particles escape from the collecting troughs, and the driving gears 101 for the rotor and for the fan are incased "in a dust-proof housing 102. In the various forms of apparatus above described the particles are fed downwardly from the hopper onto a rotating plate or element. It is not essential, however, that all portions of the means that spreads out the particles and discharges them into the air revolve, for if desired, said means may consist of a stationary plate or supporting portion 19 and a device for spreading out the particles and discharging them centrifugally from the periphery of said plate, such, for example, as a set of rotating vanes 20 arranged above the plate 19 and operated by any suitable means.

An apparatus of the construction previously described has a considerably greater capacity than an apparatus in which the separation of particles of different sizes is effected by means of screens:- it is of such simple design that there is very little liability of its getting out of order when it is in use and it can be used successfully for separating mixtures containing particles of different sizes and different densities and for classifying or subdividing the particles of each material into more or less uniform groups.

Having thus described my invention, what I claimv and desire to secure by Letters Patent, is:

1. An apparatus for the purpose described, comprising means for discharging a mass of mixed particles into the atmosphere in such a manner that they tend to separate into merging curtains of flow. containing equivalent particles, means forcollecting the particles constituting said curtains of flow in different groups, and means forsubdividing or classifying the particles in one or more of said groups into separate and distinct groups.

2. An apparatus for separating into substantially uniform groups particles of varying size or varying density, or both, comprising means for discharging a mass of mixed particles into the atmosphere in such a manner that the particles separate into curtains of flow containing equivalent particles, means for sub'ecting the falling particle to the action 0 a medium which tends to change the path of tra vel of the less dense particles, means for collecting the particles in different groups, and means for subdividing or classifying the particles in some of said groups into independent groups.

' A separating apparatus, comprising a plurality of collecting receptacles arranged in proximity to' each other, means for discharging a mass of mixed particles into the air by centrifugal action in a direction toward said receptacles, ing the falling particles to the action of a medium that retards the velocity of the less dense and smaller particles and also deflects same from their natural path of travel, and

means for subdividing the particles which enter one or more of said troughs into separate and distinct groups.

4. A separating apparatus, comprising a plurality of collecting receptacles arranged in proximity to each other, means for discharging a mass of mixed particles into the air by centrifugal action in a direction toward said receptacles, means for drawing a current of air in a general downward direction through the articles while they are traveling toward said receptacles; for the purpose described, and means in each of said receptacles for separating the small and large particles into different groups.

5. A separating apparatus, comprising a rotatable member arranged horizontally and so constructed that a 'mass of mixed particles which is supplied, to said member will be discharged centrifugally from said member when said member is in rotation. a plurality of collecting receptacles arranged at different distances from the axis of rotation of said member, and means for separating the large and small particles that enter said receptacles.

6. A- separating apparatus, comprising a rotatable member constructed so that a mass of mixed particles which is supplied to same will be discharged centri'fugally from said' member, a plurality of collecting recepceptacles arranged at different (llsttlmts from the axis of rotation of said member.

means for separating the large and small particles that enter said receptacles, and means for extracting the dust mixed with the particles.

separating apparatus, comprising screening devices, a rotatable member so constructed that a mass of mixed particles which is supplied to said member will be spread out" and discharged centrifugally tram said member toward said screening devices, and means for removing the dust that is mixed with said particles.

FRITZ KOCH.

means for subject- 

